The resource object with key 'UserName' was not found

I have migrate my web application from Old Server to New Server i.e “Windows 2003 server + IIS 6.0 + .Net Framework 3.5” to “windows 2008 R2 server + IIS 7.5 + .Net Framework 3.5. I have copy the virtual directory content from old server to new server and create a new virtual directory with new app pool(run on classic mode with .Net Frame Work v2.0 ). But when I start the application, some error is coming on browser. Please follow the error description.

“Exception message: The resource object with key 'UserName' was not found.”

I have already added the Role and features 开发者_Python百科for .net frame work 3.5. & all bineries are kept in bin folder. The same web app was run on windows 2003 server without any error.